These sensors function as cycling switches. Both sensors are located inside the evaporator housing. The air inlet sensor is normally on the right side of the housing and the air thermo sensor is normally on the left side.
The air thermo sensor detects the temperature of the air in the passenger compartment and the air inlet sensor detects the temperature of the air coming into the cooling unit. The information is input to the auto compressor control unit and the information is processed, causing the compressor clutch to cycle.
- Disconnect the sensor connector near the evaporator case.
- Measure the resistance across the wires of the suspect sensor.
The resistance specifications for the air thermo sensor at different temperatures are:
32°F (0°C) - 11.4 kilo ohms
The resistance specifications for the air inlet sensor at different temperatures are:
32°F (0°C) - 3.31 kilo ohms
- Replace the sensor if not within specifications.
REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Properly discharge the air conditioning system.
- Remove the evaporator housing and the covers.
- Unclip the sensor wires from the housing and remove the sensor(s).
- The installation is the reverse of the removal installation.
- Evacuate and recharge the air conditioning system.
- Connect the negative battery cable and check the entire climate control system for proper operation. Check the system for leaks.